1. Field of the Invention
The present invention relates to an apparatus for conveying spherical articles, and more particularly to an apparatus for supplying spherical articles, such as spherical and single crystal silicon articles, and an apparatus for converting the atmosphere through which the spherical articles are conveyed.
2. Description of the Related Art
Hitherto, semiconductor apparatuses have been manufactured by a method having the steps of forming a circuit pattern on a silicon wafer and dicing the silicon wafer as required so that semiconductor chips are formed. Under the above-mentioned circumstance, a technology has been suggested with which a circuit pattern is formed on a spherical semiconductor (a ball semiconductor) made of single crystal silicon.
When, for example, spherical single crystal silicon is employed to form discrete devices, such as solar cells or optical sensors, or semiconductor integrated circuits, a variety of processes must be performed which consist of processes for mirror-polishing and cleaning the spherical single crystal silicon, a process for forming a thin film, a process for coating resist, a photolithography process, an etching process and the like. In order to efficiently manufacture the spherical semiconductor devices, the various processes and conveying processes must be connected to one another so as to form a system line.
In the above-mentioned manufacturing system line, irregular supply of the spherical silicon from the previous process to a next process causes the quantity of the spherical silicon supplied to the next process to undesirably be changed. Thus, the processing condition in the next process must be changed. As a result, the processes cannot efficiently be performed. Therefore, the spherical articles, made of spherical single crystal silicon or the like, must sequentially and periodically be supplied to the next process at predetermined intervals. The surface of silicon can easily be oxidized. When a natural oxide film has been formed on the surface of the silicon, there arises another problem in that a metal electrode layer which will be formed on the natural oxide film suffers from unsatisfactory contact with the oxidized surface of the silicon. Therefore, it is preferable that the conveyance and processes are performed in a closed space which does not come in contact with the outside air.
In addition to gases, such as active gases and inert gases, each process is performed in a variety of atmospheres including fluids such as water and various solutions. When the processes are connected to one another to form a manufacturing line, introduction of the atmosphere for conveying spherical articles from the previous process into the following process must be prevented. That is, removal of the atmosphere of the previous process from the spherical articles is required between the processes. Then, the atmosphere must be converted into an atmosphere suitable for the following process when the spherical articles are conveyed. Moreover, the above-mentioned process requires high speed and satisfactory reliability to improve the productivity and the quality.